kernel/app/tests/fibo.cpp

// Copyright 2016 The Fuchsia Authors
// Copyright (c) 2012 Travis Geiselbrecht
//
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file or at
// https://opensource.org/licenses/MIT

#include "tests.h"

#include <err.h>
#include <inttypes.h>
#include <kernel/thread.h>
#include <platform.h>
#include <rand.h>
#include <stdio.h>

static int fibo_thread(void* argv) {
    long fibo = (intptr_t)argv;

    thread_t* t[2];

    if (fibo == 0)
        return 0;
    if (fibo == 1)
        return 1;

    char name[32];
    snprintf(name, sizeof(name), "fibo %lu", fibo - 1);
    t[0] = thread_create(name, &fibo_thread, (void*)(fibo - 1), DEFAULT_PRIORITY, DEFAULT_STACK_SIZE);
    if (!t[0]) {
        printf("error creating thread for fibo %d\n", fibo - 1);
        return 0;
    }
    snprintf(name, sizeof(name), "fibo %lu", fibo - 2);
    t[1] = thread_create(name, &fibo_thread, (void*)(fibo - 2), DEFAULT_PRIORITY, DEFAULT_STACK_SIZE);
    if (!t[1]) {
        printf("error creating thread for fibo %d\n", fibo - 2);
        thread_resume(t[0]);
        thread_join(t[0], NULL, INFINITE_TIME);
        return 0;
    }

    thread_resume(t[0]);
    thread_resume(t[1]);

    int retcode0, retcode1;

    thread_join(t[0], &retcode0, INFINITE_TIME);
    thread_join(t[1], &retcode1, INFINITE_TIME);

    return retcode0 + retcode1;
}

int fibo(int argc, const cmd_args* argv) {

    if (argc < 2) {
        printf("not enough args\n");
        return -1;
    }

    lk_time_t tim = current_time();

    thread_t* t = thread_create("fibo", &fibo_thread, (void*)(uintptr_t)argv[1].u, DEFAULT_PRIORITY, DEFAULT_STACK_SIZE);
    thread_resume(t);

    int retcode;
    thread_join(t, &retcode, INFINITE_TIME);

    tim = (current_time() - tim) / (1000 * 1000);

    printf("fibo %d\n", retcode);
    printf("took %" PRIu64 " msecs to calculate\n", tim);

    return ZX_OK;
}